Commit cf96ab1a authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Thomas Gleixner
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tools/x86/kcpuid: Protect against faulty "max subleaf" values 



Protect against the kcpuid code parsing faulty max subleaf numbers
through a min() expression.  Thus, ensuring that max_subleaf will always
be ≤ MAX_SUBLEAF_NUM.

Use "u32" for the subleaf numbers since kcpuid is compiled with -Wextra,
which includes signed/unsigned comparisons warnings.

Signed-off-by: default avatarAhmed S. Darwish <darwi@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240718134755.378115-5-darwi@linutronix.de
parent 5dd7ca42

tools/arch/x86/kcpuid/kcpuid.c

+5 −7
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <getopt.h>



#define ARRAY_SIZE(x)	(sizeof(x) / sizeof((x)[0]))

#define min(a, b)	(((a) < (b)) ? (a) : (b))



typedef unsigned int u32;

typedef unsigned long long u64;
@@ -206,12 +207,9 @@ static void raw_dump_range(struct cpuid_range *range) 
#define MAX_SUBLEAF_NUM		64

struct cpuid_range *setup_cpuid_range(u32 input_eax)

{

	u32 max_func, idx_func;

	int subleaf;

	u32 max_func, idx_func, subleaf, max_subleaf;

	u32 eax, ebx, ecx, edx, f = input_eax;

	struct cpuid_range *range;

	u32 eax, ebx, ecx, edx;

	u32 f = input_eax;

	int max_subleaf;

	bool allzero;



	eax = input_eax;
@@ -256,7 +254,7 @@ struct cpuid_range *setup_cpuid_range(u32 input_eax) 
		 * others have to be tried (0xf)

		 */

		if (f == 0x7 || f == 0x14 || f == 0x17 || f == 0x18)

			max_subleaf = (eax & 0xff) + 1;

			max_subleaf = min((eax & 0xff) + 1, max_subleaf);



		if (f == 0xb)

			max_subleaf = 2;